Abstract

Although the exact etiology of Behçet's disease (BD) remains unclear, a complex interaction between T cells and antigenpresenting cells is known to be involved in the immunopathogenesis of BD. This study aimed to identify differentially expressed cell surface markers of peripheral blood mononuclear cells (PBMCs) in active and inactive stage of BD patients. PBMCs were isolated from six healthy controls, eight inactive BD patients and five active BD patients. Different cell phenotypes were analyzed by flow cytometry, serum cytokine levels were detected by ELISA and the morphological structure of polymorphonuclear neutrophils (PMN) was revealed by transmission electron microscope (TEM). The CD11b monocyte marker was slightly decreased in active BD patients (91.5±10.9%) compared with healthy controls (97.5±1.3%), but was not different compared to inactive BD patients (88.8±12.2%). The CD14 monocyte marker was significantly increased in active BD patients (28.9±18.7%, p=0.05) and inactivate BD patients (30.8±21.4%, p=0.08) compared to healthy controls (11.1±3.7%). However, CD16 (FcγRIIIA) was higher in inactive BD patients (93.9±2.4%) than active BD patients (85.3±14%), and CD32 (FcγRII) was down-regulated in active BD patients (26.6±18.1%) compared to inactive BD patients (46.6±30.3%) and healthy controls (71.7±17.4%; p=0.002). Most surprisingly, the mannose receptor marker CD206 was highly expressed with significance in active BD patients (49.7±35.2%) compared to healthy controls (7.4±0.8%) (p=0.02) and inactive BD patients (4.7±3.1%) (p=0.007). In spite of the up-regulation of CD206 in active BD patients, interleukin-10 was markedly increased in the inactive state after improving medication than in the active state. All these findings show that differential surface expression of PBMCs between the inactive and active state of BD patients may influence changes of the disease state following treatment.

Keywords: Behçet's disease, monocyte/macrophage, active and inactive stage, surface markers